Coloration of organic derivatives of cellulose



' Patented Dec. 20, 1 938 UNITED STATES COLORATION OF ORGANIC DERIVATIVES OF CELLULOSE James G. McNally and Joseph B. Dickey, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y.

Jersey ,.a corporation 01' New No Drawing. Application January. 14, 1937,

' Serial No. 120,559

. 19 Claims.

This invention relates to the dyeing or coloration of organic derivatives of cellulose. More particularly it relates to the dyeing or coloration of organic derivatives of cellulose, such as cellu- 5 lose acetate, with nuclear non-sulfonated aromatic azo derivatives of barbituric acid and substituted barbituric acids.

' Organic derivatives'of cellulose are characterized by an indifierent affinity for the usual cot- ]0 ton or wool dyes, especially the ordinary water soluble dyes. Typical organic derivatives of cellulose include the hydrolyzedas well as the unhydrolyzed cellulose organic acid esters, such as cellulose acetate, cellulose formate, cellulose propionate or cellulose butyrate, and the hydrolyzedas well as the unhydrolyzed mixed organic acid esters of cellulose, such as cellulose acetatepropionate, cellulose acetate-butyrate, and the cellulose ethers, such as methyl cellulose, ethyl 2O cellulose or benzyl cellulose,

We have discovered't'nat the nuclear non-sulfonated aromatic azo derivatives of barbituric acid and substituted barbituric acids constitute a valuable class of compounds which may be em- 25 ployed for the dyeing or coloration of materials made of or containing organic derivatives of cellulose. The nuclear sulfonated aromatic azo barbituric compounds, that is, compounds in which there is a sulfonic acid group attached directly to the aromatic nucleus, possess less or no utility for the coloration of organic derivatives of cellulose but may be employed for the coloring of cotton, natural silk or wool by customary methods of application. The term substituted 35 barbituric acids is intended to be used in its broad sense and includes, for example, compounds such as thiobarbituric acid, 2-iminobarbituric acid, 2-methyliminobarbituric acid, 2-imino-3- fcyano-barbituric acid. 6-iminobarbiturie acid "and S-inundthio-barbiturlc acid as more fully set forth hereinafter. t

In accordance with the process of our invention, dyeings having unusuallygood fastness to light and washing may be produced on organic derivatives of cellulose. These dyeings are, in general, of good clarity and may be produced in a variety of shades. The dyeing properties of the aromatic azo barbituric dye compounds employed in the process of our invention will be fully apparent from the description given in connection have, ina fewisol ated cases, been disclosed as dyes for cotton and wool. So far as is known to us, however, there is no teaching or disclosure anywhere that aromatic azo derivatives of barbituric acid and substituted barbituric acids can be employed for the dyeing or coloration of organic derivatives of cellulose. Again, many of the azo derivatives disclosed herein constitute new classes of compounds as will be more full pointed out.

In order that our invention may be completely understood the general formulae of a number of classes of compounds, which may be employed in the process of the invention, together with specific examples of compounds represented by the general formulae will be given. It will be understood that the compounds disclosed are given for purposes of illustration and are not intended to limit the invention. For purposes of reference the formulae are numbered consecutively.

Because the barbituric nucleus is not always numbered the same by all persons, to avoid any I possible ambiguity,

the numbering followed throughout the specification and claims is given hereinafter in connection with the formulaeillustrating the classes of compounds included within the scope of the invention.

Dyeings of good stability to light, heat, washing and ironing can be produced on materials containing organic derivatives of cellulose, such as cellulose acetate, by applying thereto a dye selected from the class of compounds having the general formula:

wherein X is O or S, R is a nuclear non-sulfonated aryl nucleus which may have one or more substituents such, for example, as an alkyl group,

an alkoxy group, --NOz, --OH, --OC2H4OH orbarbituric acid and substituted barbituric acids having a non-metallic,univalent substituent on the aryl nucleus in ortho position to the azo group may be employed to advantage in the process of the invention as these compounds have been found to produce dyeings on organic derivatives of cellulose particularly good with respect to light fastness. Said univalent substituent may be an alkoxy group such as OCH3, --OC2H5 or OCH2CH2CH3, a nitro group, an --OC2H4OH group, an alkyl group such as methyl, ethyl or propyl, a halogen atom such as chlorine, bromine or fluorine, or an aryloxy group, such as phenoxy, for example.

While the presence of a. univalent non-metallic substituent on the aryl nucleus in ortho position to the azo group generally improves the dyeing properties it has been found that certain substituents, in given cases, exert a greater beneficial effect than others. To illustrate, the alkoxy and aryloxy groups exert a generally greater eifect on the compounds of our invention and especially those represented by the general formula I than the other substituents. The effect of the alkoxy and aryloxy groups is most pronounced in the case of barbituric acid. An exception to the general rule just stated exists in the case of thicbarbituric acid, a compound of Formula I. In that case it has been found that the nitro group produces a greater effect than either the alkoxy or aryloxy group. This is especially so where the aryl nucleus contains, as sole substituents, a nitro group in ortho position to the azo group and a chlorine atom in para position to the azo p.

The compounds of our invention may be prepared by diazotizing a primary aromatic amine and coupling the diazonium salt formed with a barbituric acid compound, capable of coupling in the -position, in an alkaline medium to form the desired azo derivative. Coupling may also be carried out in an acid or neutral medium but generally it is more satisfactory to conduct the coupling reaction in an alkaline medium as the reaction ordinarily proceeds more readily therein. Thus,

compounds having the general Formula I can be prepared by diazotizing a primary aryl amine and coupling in an alkaline medium with a barbituric acid having the general formula:

wherein X and R1 have the meaning previously assigned to them.

Dye compounds represented by Formula I color organic derivatives of cellulose yellow shades ranging from greenish-yellow to orange-yellow, and in certain cases red, but cause substantially no coloration on cotton or viscose. Because of the property just noted these dyes may be employed to produce cross-dyeing effects on fabrics, for example, containing an organic derivative of cellulose with either cotton or viscose or'both cotton and viscose.

The preparation of the compounds having the general formula I will be clear from the following representative examples illustrating their preparation. Unless otherwise indicated quantities are expressed in parts by weight.

Example 1 27.4 grams of 2,4-dinitroaniline are dissolved in 36.5 cc. of concentrated sulfuric acid (Sp. Gr. 1.84 the resulting solution is cooled to a temperature approximating 05 C., for example, and diazotized by the addition of a cooled solution of 11 grams of sodium nitrite dissolved in 56 cc. of concentrated sulfuric acid.

16.4 grams of barbituric acid are dissolved in a minimum amount of an aqueous sodium hydroxide solution. The resulting solution is iced and the diazo solution prepared above slowly added with stirring. Sodium hydroxide may be added as necessary to maintain the solution in an alkaline condition. Upon completion of the coupling reaction the mixture is diluted with water and the desired azo dye compound is recovered by filtration, washed with water and dried.

Example 2 15 grams of p-amlno acetanilide are dissolved in 200 cc. of water containing 25 cc. of 36% hydrochloric acid. The resulting solution is cooled to a temperature approximating 0:5 C. by the addition of ice and diazotized by the addition of 6.9 grams of sodium nitrite dissolved in water.

12.8 grams of barbituric acid are dissolved in Example 3 13.8 grams of o-nitroaniline 'are dissolved in a mixture of 25 cc. of water and 25 cc. of 36% hydrochloric 'acid. The resulting solution is cooled and diazotized in the usual manner by the addition of a concentrated aqueous solution of 6.9 grams of sodium nitrite.

13.7 grams of cresidine are dissolved in 50cc. of water containing. cc. of 36% hydrochloric acid, the solution is iced, and the diazonium solution prepared above is added with stirring. Upon completion of the coupling reaction the resulting brown paste is thinned with water, acidified further with 10 cc. of 36% hydrochloric acid and diazotized by the addition of a concentrated aqueous solution of 6.9 grams of sodium nitrite. The diazo solution resulting is added with stirring to 16.4 grams of barbituric acid dissolved in water, containing sodium carbonate. After complete coupling the mixture is acidified and the dye formed recovered by filtration.

Example 4 15.3 parts of /3hydr0Xy-o-ethoxyaniline,

oozrnon are dissolved in 200 parts of water and ice conto litmus paper with acetic orhydrochloric acid and the dye is filtered, washed with water and dried.

Example 5 16.7 parts of e-methoxy-o-phenetidine,

are diazotized in the usual manner with an aqueous solution of sodium nitrite.

12.8 parts of barbituric acid are dissolved in 200 parts of water containing 31 parts of sodium carbonate and coupled with the diazo solution prepared above in accordance with the method described in Example 4. The dye compound formed is recovered by filtration and subjected to any further purification desired.

acid in a similar manner as described in Example 4. The dye compound formed may be recovered by filtration and subjected to any further treatment desired.

Example 7--Preparation of S-ethyl-S (o-methoxy benzene azo) barbituric acid To a cooled solution of 12.3 grams of o-meth oxyaniline in 200 cc. of water. containing 30 cc. of 36% hydrochloric acid are added a concentrated aqueous solution of 6.9 grams of sodium nitrite. The diazo solution resulting is added gradually to an iced solution of15.6 grams of 5-ethylbarbituric acid dissolved in water containing an excess of sodium hydroxide. After complete coupling the dye compound formed is precipitated out by adding an acid and is recovered by filtration.

Other 5-substit'uted barbituric acids are coupled in the same manner. By the substitution, for example, of 20.5 grams of S-phenylbarbituric acid for 5-ethylbarbituric acid of the example, 5-phenyl-5-o-methoxy benzene azo barbituric acid may be prepared. Similarly, by the substitution of 22 grams of 5-benzylbarbituric acid for 5-ethylbarbituric acid, 5-benzyl-5-o-methoxy benzene azo barbituric acid may be prepared.

As will be understood amines,- other than methoxyaniline, may likewise be employed.

Example 8 The resulting diazo solution is added I Example 9 18 grams of 6-methoxy-l-aminobenzothiazole,

OCH:

are dissolved in a warm mixture of 60 grams of water and 25 grams of formic acid. The resulting solution is cooled and added to a cold solution of 50 grams of water and 110 grams of sul furic acid (Sp. G1. 1.83). The amine is then diazotized at C. by the addition of a concentrated aqueous solution of 6.9 grams of sodium nitrite.

12.6 grams of barbituric acid are dissolved in 200 parts of water containing 31 parts of sodium carbonate. The resulting solution is cooled and the diazo solution prepared above is added dropwisewith stirring. When coupling is complete the mixture is made acid to litmus with acetic acid and the precipitated dye is filtered, washed and dried. The dye formed colors cellulose acetate greenish-yellow shades'from its aqueous suspensions.

Thiobarbituric acid may be substituted for barbituric acid in the above example.

Example 10 9.9 grams of Z-aminothiazole,

are diazotized as described in Liebigs Annalen, volume 448, page 210 (1926).

14.2 grams of thiobarbituric acid are dissolved in an aqueous sodium carbonate solution and coupled with the diazotized Z-aminothiazole in the manner described in Example 9. The dye formed may be recovered by filtration, washed and dried. Cellulose acetate is colored a greenish-yellow shade from an aqueous suspension of the dye. 4

A second class of compounds included within the scope of the invention and which may be employed for the dyeing of organic derivatives of cellulose has the general formula:

O=CN

e 1 5 2 n. RN=NCH C=NH wherein R. represents a substituted or unsubstituted aromatic nucleus. Advantageously, R is an aryl nucleus of the benzene series.

These compounds are described and claimed in our co-pending application Serial No. 97,026, filed August 20, 1936. Saidapplication Serial No. 97,026 likewise claims the process of coloring organic derivatives of cellulose, the process of preparing said compounds, and material containing an organic derivative of cellulose colored with a dye selected from the class of compounds represented by the general Formula II.

The nuclear non-sulfonated aromatic azo compounds having the general formula just given produce dyeings on materials made of or containing organic derivatives of cellulose which are in general of good fastness to light and washing and range in shade from greenish-yellow to red. The nuclear sulfonated azo compounds having, said general formula are not suitable for the acid to litmus by the addition of acetic acid and coloration of organic derivatives of cellulose but may be employed for the coloration of cotton, wool, natural silk and regenerated cellulose by the customary methods of application.

In general, the nuclear non-sulfonated azo compounds having the Formula II also color natural silk and wool but have very-little aflinity for cotton or viscose fibres. Because of their selective dyeing properties, these nuclear nonsulfonated compounds may be employed to produce cross dyeing efiects on fabrics, for example, containing an admixture of an organic derivative of cellulose, natural silk or wool with cotton or viscose.

Further, the non-sulfonated aryl azo compounds represented bylthe Formula 111 possess the advantage of being soluble inorganic solvents such as acetone and cellosolve acetate, for example, and may be used to color lacquers, plastic masses and the like. In general, any solvent for cellulose acetate or more broadly for lacquer, plastic masses and the like, which is also a solvent for the dye compound, may be used.

The aromatic azo compounds represented by the general Formula II can be prepared by diazoatizing an arylamine and coupling, the diazonium salt formed with 2-imino-3-cyano-barbituric acid in an alkaline medium.

The following examples will illustrate the method of preparation of the azo compounds having the above formula. Quantities are expressed in parts by weight.

Example 1 13.7 parts of o-phenetidine are dissolved in 200 parts of water containing about 36 parts of 36% hydrochloric acid. The resulting solution is cooled to a temperature approximating 0-5 C. by theaddition of ice, for example, and 'diazotized by the addition of 6.9 parts of sodium nitrite dissolved in water.

13.8 parts of -2-imino-3-cyanobarbituric acid are dissolved in 300 parts of Water containing 31.8 parts of sodium carbonate. The resulting solution is cooled and the diazo solution prepared above is slowly added with stirring. After coupling is complete, the alkaline mixture is made the precipitated azo compound is filtered, washed and dried.

Example 12 20.7 parts of 2,6 dichloro-l-nitroaniline are dissolved in 55 parts of sulfuric acid and the resulting solution cooled. This solution is then mixed with a cold solution of 6.9 parts of sodium nitrite in 37 parts of 100% sulfuric acid. The resulting solution is further cooled externally and diluted by the addition of parts of glacial acetic acid and cooled to 15 C. The mixture is stirred several hours until the diazotizatl on is complete after which it is added to a cold solution of 13.8 parts of 2-imino-3-cyano-barbituric acid dissolved in 105 parts of glacial acetic acid. Sodium acetate is then added until the sulfuric acid present is neutralized. When coupling is complete, the desired azo compound is precipitated by the addition of water, filtered, washed and dried.

Example 13 The resulting mixture is addition of 6.9 parts of sodium nitrite dissolved in water.

13.8 parts of 2-imino-3-cyanobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate. The solution thus prepared is well cooled and the diazo solution prepared above slowly added thereto with stirring. After coupling is complete, the alkaline mixture is made acid to litmus with acetic acid and the precipitated azo compound filtered, washed and dried.

. Example 14 34.? parts of. disodium 2-amino-nap-hthalene-4,

S-disulfonate are dissolved in 200 parts of water.

The resulting solution is well iced and then 59.5 parts of 36% hydrochloricacid are added with Example 15 13.6 parts of p-aminodimethylaniline are dissolved in 200 parts of water containing about 47.6 parts of 36% hydrochloric acid and diazotized in the usual manner by the addition of an aqueous solution of 6.9 parts of sodium nitrate. The diazo solution thus prepared is added slowly to a well stirred iced solution of 13.8 parts of 2- imino-3-cyanobarbituric acid dissolved in 300 parts of water containing 30 parts of sodium carbonate. made acid to litmus with acetic acid and the desired azo compound is recovered by filtering, washed and dried. l

A third class of compounds included within the scope of the invention and which may be employed for the dyeing of organic derivatives'of cellulose has the general formula:

wherein R represents hydrogen, an alkyl group,

'or an aryl group, X represents oxygen, NH or sulfur, Y represents 0 or NR and R is an aromatic nucleus which may be substituted or un- After about one hour, the mixture is substituted. Advantageously, R is an aryl nuan alkaline medium with compounds of the. type.

represented by the formula:

' N=CNH Y='o-N ir wherein R represents hydrogen, an alkyl group or an aryl group, X represents, oxygen, NH or sulfur and Y represents 0 or NR.

The compounds having the general Formula III, the process of coloring organic derivatives of cellulose and material containing an organic derivative of cellulose colored with a dye selected from the class of compounds represented by the general Formula III are described and claimed in our. copending application Serial No. 120,557

- filed January 14, 1937 (now United States Letters yellow to red,

Patent No. 2,121,811, dated June28, 1938).

As previously indicated, the nuclear non-sulfonated azo compounds represented by'the general Formula III may be employed for the dyeihg or coloration of materials made of or containing organic derivatives of cellulose. The

dyeings' produced employing said non-sulfonated of preparation of the azo compounds represented by the general Formula III. Quantities are. expressed in parts by weight.

Example 16 13.? parts of o-phenetidine are dissolved in 200 parts of water containing about 36 parts of 36% hydrochloric acid. The resulting solution is cooled to a temperature approximating -5 'C. by the addition of ice, for example, and diazotized by adding, with stirring, 6.9 parts of sodium nitrite dissolved in water.

12.7 parts of 6-iminobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate. The resulting-solution is cooled and the diazo solution prepared above is added with stirring. Upon completion of the coupling reaction, the mixture is made slightly acid to litmus with acetic acid and the precipitated dye filtered, washed with water, and dried.

Example 17 16.8 parts of o-methoxy-p-nitroaniline' are added to 200 parts of water containing 36 parts of 36% hydrochloric acid. The mixture is iced and diazotized by adding, with stirring, 6.9 parts of sodium nitrite dissolved in water.

14 parts of fi-methyliminobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate and coupled in the usual manner with the diazo solution prepared as described above. When coupling is complete, the mixture is made slightly acid to litmus with acetic acid and the desiredazo compound is recovered by filtration, washed with water, and

dried.

Example 18 I 34.7 parts of disodium-2-aminonaphthalene- 4,8-disulfonate are dissolved in 200 parts of water. The solution is well iced and then 59.5 parts of 36% hydrochloric acid are added with vigorous stirring. The resulting mixture is diazotized by the addition, with stirring, of 6.9 parts of sodium nitrite dissolved in water.

12.7 parts of fi-iminobarbituric acid are dis- -compound is filtered, washed Example 19 13.6 parts of p-aminodimethylaniline are dissolved in 200 parts of water containing about 47.6

parts of 36% hydrochloric acid. The resulting solution is cooled to a temperature approximating 0'-5 C. by the addition of ice and. diazotized in the usual manner by the addition of 6.9 parts of sodium nitrite dissolved in water.

12.7 parts of 6-iminobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate. The solution is iced, and the diazo solution prepared as described above is slowly added with stirring. When coupling is complete, the mixture is made slightly acid to litmus with acetic acid and the precipitated dye is filtered, washed with water and dried.

Example 20 16.8 parts of o-methoxy-p-nitroaniline are added to 200 parts of water containing about 36 parts of 36% hydrochloric acid and the mixture is diazotized in the usual manner by the addition of 6.9 parts of sodium nitrate dissolved in water. I

14.3 parts of G-iminothiobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate and coupled in the usual manner with the diazo, solution prepared above. Upon completion of the coupling reaction, the mixture is made slightly acid to litmus with acetic acid and the precipitated dye is filtered, washed with water and dried.

Example 21 17.3 parts of o-nitro-p-chloroaniline are tized in the usual manner.

14.3 parts of G-iminobarbituric acid are dissolved in a cold dilute aqueous solution of sodium hydroxide and the diazo solution prepared above is added with stirring. When coupling is complete, the mixture is made acid to litmus with acetic acid, for example, and the precipitated dye with water and diazodried.

Example 22 13.! parts of o-phenetidin'e are dissolved in 200 parts of water containing about 36 parts of 36% hydrochloric acid. The resulting solution is. cooled to a temperature approximating 0-5 C.

by the addition of ice, for example, and diazotized by adding, with stirring, 619 parts of sodium nitrite dissolved in water. i

12.6 parts of 4,6-diiminobarbituric acid are dissolved in 300 parts of water containing 31 parts 01' sodium carbonate. The resulting solution is cooled and the diazo solution prepared above is added with stirring. When coupling is complete the mixture is made acid to litmus. with acetic acid and the precipitated dye is recovered by filtration, washed with water and dried.

Example 23 13.5 parts of p-aminoacetophenone are diazotized in the usual manner.

14.2 parts of 4,6-diiminothiobarbituric acid are dissolved in 300 parts of water containing 30 parts .of sodium carbonate.

The resulting solution is cooled and the diazo solution prepared above is added with stirring. Upon completion of the coupling reaction the mixture is made slightly acid to litmus with acetic acid and the precipitated dye is recovered by filtration, washed and dried.

Example 24 16.8 parts of o-methoxy-p-nitroaniline arev Example 25 20.? parts of 2,6-dich1oro-4-nitroaniline are dissolved in 55 parts of sulfuric acid and the resulting solution cooled. This solution is mixed with a cooled solution of 6.9 parts of sodium nitrite in 37 parts of 100% sulfuric acid. The resulting solution is further cooled externally and then diluted by the addition of parts of glacial acetic acid and cooled to 15 C. The mixture is stirred until diazotization is complete, usually several hours, after which it is added to a cooled solution of 12.7 parts of 6- iminobarbituric .acid dissolved .in 105 parts of glacial acetic acid. Sodium' acetate is then added until the sulfuric acidpresent is neutralized. When coupling is complete, the dye compound formed is precipitated by the addition of water after which it is filtered, washed and dried.

A further class of compounds representative of those which may be employed in the process of our invention has the general formula:

wherein X represents hydrogen or an alkyl group and R is an aromatic nucleus which may be' or 2-alkyliminobarbituric acid, having the following formula:

wherein X represents hydrogen or an alkyl group.

The term alkyl as used above is intended to include nonsubstituted alkyl groups, such as methyl, ethyl, propyl, etc., as well as substituted alkyl groups, except as otherwise indicated, such as -C2H4OH, C3H6OH and -C2H4C1, for example.

The compounds represented by Formula IV, the process of coloring organic derivatives of cellulose with a dye selected from such compounds and material made of or containing an organic derivative of cellulose colored therewith are described and claimed in our copending application Serial No. 120,556, filed January 14, 1937 (now, United States Letters Patent No. 2,103,269, dated December 28, 1937).

As in the case of the other classes of compounds chosen to illustrate the invention the nuclear non-sulfonated aromatic azo derivatives represented by Formula IV constitute valuable dyes for the dyeing or coloration of organic derivatives of cellulose. The dyeings produced therewith are in general of good fastness to light and washing and range in shade from greenishyellow to red. ,The nuclear sulfonated azo compounds possess little or no utility for the colora- 13.7 parts of Q-phenetidine are dissolved in 200 parts of water containing about 30 parts of 36% hydrochloric acid. The resulting solution is cooled to a temperature approximating 05 C. by the addition of ice, for example, and diazotized in the usual manner by the addition of 6.9 parts of sodium nitrite dissolved in water.

12.7 parts of Z-iminobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate and coupled in the usual manner with the diazonium solution prepared above. Upon completion of the coupling reaction, the mixture is made acid to litmus with acetic acid and the precipitated azo compound is filtered, washed with water, and dried.

Example 27 16.8 parts of o-methoxy-p-nitroaniline are added to 200 parts of watercontaining about 36 parts of 36% hydrochloric acid. The mixture is iced and diazotized in the usual manner by adding with stirring 6.9 parts of sodium nitrite dissolved in water. i I

14. parts of 2-methyliminobarbituric acid are dissolved in 300 parts of water containing 31.8 parts of sodium carbonate. The resulting solution is cooled and the diazo solution prepared as described above is added with stirring. When coupling iscomplete, the mixture is made acid to litmus with acetic acid and the precipitated dye compound is filtered, washed with water, and dried.

Example 28 34.7 parts of disodium-2-aminonaphthalene- 4,8-disulfonate are dissolved in 200 parts of water. The solution is Well iced and about 59.5 parts of 36% hydrochloric acid are then added with vigorous stirring. The resulting solution is then diazotized by the gradual addition of 6.9 parts of a concentrated water solution of sodium nitrite natural silk or wool by customary methods of application.

Example 29 parts of 36% hydrochloric acid and diazotized in of sodium carbonate.

I parts of sodium carbonate.

the usual manner by the addition of 6.9 parts of sodium nitrite dissolved in water.

12.7 parts of 2-iminobarbituric acid are dis: solved in 300 partsof water containing 31.8 parts The resulting solution is cooled and the diazo solution prepared as described above slowly added with stirring. When coupling is complete, the mixture is made slightly acid to litmus with acetic acid and the desired azocompound is recovered by filtration, washed with water, and dried.

. Example 30 15.8 parts of o-nitro-p-chloraniline are added to 200 parts of water containing about 36parts of 36% hydrochloric acid. The mixture is iced and diazotized in the usual manner by adding with stirring 6.9 parts of sodium nitrite dissolved in water.

14.1 parts of 2-methy1iminobarbituric'acidare dissolved in 300 parts of water containing 30 The resulting solution is cooled by the addition of ice, for example,

and the diazo solution prepared as described above is added with stirring. When coupling is complete, the mixture is made neutral to Congo red paper by the addition of acetic acid and the desired azo compound is recovered by filtration, washed with water, and dried.

Example 31 g 15.4 parts of o-nitro-p-methoxyaniline are diazotized and coupled with 15.9 parts of. 2-ethyliminobarbituric acid dissolved in a dilute aqueous solution of sodium carbonate. The dye compound formed is recovered by filtration and subjected to any further treatment desired.

2-5-hydroxyethyliminobarbituric acid, for ex: ample, may be substituted for 2-ethyliminobarbituric acid in the above example.

In order that our invention'may be fully understood, the preparation of a number of substances used in the manufacture of the azo compounds employed in the process of our invention is described hereinafter. For purposes of clarity the number of the formula is given immediately preceding the disclosure of the preparation of those v substances useful in connection with the manurates on acidifying the filtrate with hydrochloric acid and maybe recovered by filtration.

5 -ethyl thiobarbituric acid This compound may be prepared accordingto the method described for 5-ethyl barbituric acid by substituting a molecular equivalent weight of thiourea for urea.

5-benzyl and 5-phenyl barbituric acid These compounds may be prepared in a similar manner to that described for 5-ethyl barbituric ethanol.

solved in a small volume of water and the resultacid by substituting equivalent molecular proportions of benzyl diethyl malonate and phenyl diethyl malonate, respectively, for ethyl diethyl malonate. Other aralkyl and aryl barbituric acids may be prepared in similar fashion by the use of the corresponding aralkyl or aryl diethyl malonate.

5-benzyl and S-Phenyl thiobarbz'turz'c acid These compounds may be prepared in a similar manner to that described for 5-ethyl thiobarbituric acid by substituting equivalent molecular proportions of benzyl diethyl malonate and phenyl diethyl malonate, respectively, for ethyl diethyl malonate. Other aralkyl and aryl thiobarbituric acids may be prepared in similar fashion by the use of the corresponding aralkyl or aryl diethyl malonate.

FORMULA II 2-imino-3-cyanobarbituric acid 23 grams of sodium are dissolvedin 200 cc. of anhydrous ethonal and 160 grams of ethyl malonate are added following which 46 grams of dicyandiamide are added. The reaction mixture is heated on a steam bath at C. for about 10 hours and the resulting mixture poured into 2500 cc. of cold water and neutralized with dilute hydrochloric acid. The '2-imino-3-cyanobarbituric acid that separates is filtered, washed with water and dried.

FORMULA III 6-iminobarbituric acid 4.6 grams of sodium are dissolved in cc. of absolute ethanol and 11.3 grams of ethyl cyano acetate and 6.5 grams of -urea are added. The mixture is heated at ,708p-C. for about 5 hours and the sodium salt resulting is filtered, washed with alcohol and dissolved in a minimum amount of water. G-iminobaibituric acid is precipitated by adding hydrochloric acid to the aqueous solution of its sodium salt until the solution is acid to Congo red paper, recovered by filtration, washed with water and dried.

. fi-imz'nothiobarb'ituricacid This compound is prepared in the same manner as G-iminobarbituric acid, except that an equivalent amount of thiourea is substituted for urea.

' FORMULA IV Z-methyliminobarbitaric acid To a solution of 9 grams of sodium in cc. of dry ethanol are added 36 grams of diethylmalonate and 23.4 grams of methyliminourea (methyl guanicline) carbonate. The mixture is refluxed for 5 hours, after which it is filtered and the precipitate washed with a small amount of The sodiiun salt thus obtained is dising solution acidified to Congo red paper by the addition of hydrochloric acid. Z-Methyliminobarbituric acid separates on cooling and is recovered by filtration, washed and dried.

Z-z'mz'nobarbituric acid This compound can be prepared as described in Liebigs Annalen, vol. 335, page 352 (1904) or Berichte der Deutschen Chemischen Gesellschaft, Vol.26, pagev2553 '(1893).

2-ethylim inobarbituric acid To a solution of 9 grams of sodium in 150 cc. of dry ethanol are added 36 grams of ethyl malonate and 26.5 grams of ethyliminourea carbonate (ethyl guanidine). The mixture is refluxed for hours, after which it is filtered and the precipitate washed with ethyl alcohol. The sodium salt thus obtained is dissolved in a small volume of water, and the resulting solution acidified to Congo red paper by means of hydrochloric acid to precipitate Z-ethyliminobarbitdric acid. The desired product separates on cooling and is recovered by filtration, washed and dried.

Ethyliminourea carbonate may be prepared as described in Science Papers Institute Physical Chemical Research (Tokyo), vol. 16, pages 306- 309, 24-28 (1931).

Z-p-hydroxy ethylirninobarbituric acid To a solution of 9 grams of sodium in 150 cc. of dry ethanol are added 36 gramsof ethyl malonate and 29.2 grams of fi-hydroxy ethyliminourea carbonate (prepared as described in the above reference). The mixture is refluxed for '5 hours,

after which it, is filtered and the precipitate washed with ethyl alcohol. The sodium salt thus obtained is dissolved in a small volume of water" and the resulting solution acidified'to Congo red paper by means of hydrochloric acid to precipitate 2-r3-hydroxyethyliminobarbituric acid. The desired product separates on cooling and is recovered by filtration, washed and dried.

The following tabulations further illustrate the compounds employed in the process of our invention together with the color they produce on cel- Compounds represented by Formula I Coupling component Color on cellulose Amine acetate 511k Barbituric acid o 5-phenyl barbituric 801d fi-phenyl (p-chlor) barbitnric acid.

Barilgituric acid m-Nitroaniline. Greenish-yellow.

o-Nitroaniline D Aniline Do. o-Methoxy aniline. Do. i-aminoazobenzena. Do. p-Aminoacetophenone. Do. 1-amino-2, 4-dinitrobenzene Do. 2, fi-dimethylaniline Do. p-Aminoacetanilide Do. l-amino--nitro-fi-methoxy benzene Do. o-Ethoxy aniline Do. p-Methoxy aniline. Do. 0-Ch1or0aniline Do. o-Methylaniline Do. 1-amino-3-chlor-6- ydroxy benzene Do. l-amino-3-chlor-6 methoxy benzene; Do. -Naphthylamine. Do. m-Methylaniline Do. Do. Do. Red.

Do. Greenish-yellow.

Do. Do. D o p-Methylaniline. Do. in-Chloroaniline. D0. o-Ethoxyaniline. Do. o-Nitroaniline Do. p-Aminoacetamhde D0. o-Methoxyaniline D0. o-Etlioxyaniline Do. o-Propoxyaniline D0. o-fl-Metlioxy ethoxy (00111400111) aniline- D0. o-Phenoxyaniline DO. o-Ethoxy-p-Chloroaniline Do. o-Methoxy-p-methylaniline T D0. o-B-Hydroxyethoxy (O C:H4OH) aniline- Do. o-Nitro-p-chloroaniline Do. o-Nitroaniline Greemsh-o r a n g e yellow. o-Nitro-p-chloroaniline D0. o-Nitro-p-bromoanilin Do. o-Nitro-p-fluoroaniline Do. o-Nitro-p-methylaniline go. o.

o-Nitro-p-metlioxyaniline Compounds represented by Formula II the sulfonated compoun diazotized', 2-amlnonaphthalene- 4,8-disulronic acid, 'diazotlzed p-nltroaniline-o-sulfonic acid or diazotized 1-amlno-4-naphthol-5-sultonlc acid in ds prepared by coupling 7 I 2,140,588 As afurther illustration of the compounds represented by Formula 11 reference may be made to Compounds represented by Formula III Color on cellulose Cgjupling component Amino acemte Silk fi-alkylimiuobarblturic acido-Anisidino Greenish-yellow. c-iminothlobarbituric ac d. do. Golden-yellow.

liminobarbituric aci p-Anisidlne Greenish-yeliuw. fl-lmrnothlooarbitunc acid .do. Golden-yellow. fi-immobarbltunc acid... 0-Chl01'nani A greenishqenow.

- G-alkyliminobarbrtunc acid. Do. B-lminobarbituric acid- Red. fi-alkyiiminobarbituric acid- D0. 6-lminothiobarbituric ac1d- Do. G-unlnobarbituric acid Golden-yellow. c-aikylimmobarbituric acid Do. c-iminothiobarbiturlc acid. ..do- Do. p-lminobarbituric acid o-Methcxy-p-nitroanilinc Do.

"o-alkyllmlnobarblturic acid I .....d Do.

c-lminothiobarbituric i Do. c-iminobarbituric acid ofi-Hydroxyethcxyaniline. Orange-yellow. G-iminobarbituric acid- O-Nl'trnanilina Golden-yellow. c-methyliminobarbituric aci do Do. fi-iminothiobarbituric acid. ...-.do Do. G-mcthyliminothiobarbituric acid do Do. G-iminobarbituric acid o-Nitro-p-chloroaniline Do.

6, iminothiobarbiturlc acid rin Do. B-methyliminothiobarbituric acid ....-do Do. G-iminobarbituric acid Z-nitro-i, S-dichloroanlllnc Do. c-mcthyiiminobarbituric aci do Do. O-iminothiobarblturic acid .do Do. fi-mcthyliminothiobarbituric acid. .do Do. G-iminobarbituric acid 2, 6-dinitro-i-chlor0aniline D0. B-methylimiuobarbituric acid. do Do. c-iminothiobarbituric acid. do Do. G-mcthyliminothiobarbituric aci 0 Do. o-imlnobarbituric acid. Do. G-methyliminobarbiturlc Do.

. G-lminothiobarblturic acid. Do. G-mothyliminothiobarbitur Do. o-iminobarbitu'ric acid Do. c-gnethyliminobarbituric acid- Do. G-Iminothiobarbituric acid.- .do Do. c-mcthylimipothiobarbitmic acid ..do D0.

v-ifv-iminobz u-blturic acid 2-mtro-l-ammo-4 Do. o-mqthyliminobarbitmic acld.. do Do. o-immothiobarbituric acid .do. Dc. 6-mcthyliminothiobarbituric acid .-do Do. O-iminothiobarbituric acid.- oC'hlomaniHm Do. 4, o-diiminobarbituric acid Y 4:11am Yellow D0 m-Aniqiriima D0. p-Anisldine Do. o-Chlcroaniline Do. m-Chlnmaniiinn D0, p-Chloroaniline Do. o-Rrnmnanilina Orange-yellow. m-Rmmnnnilinn D0. p-Rmmnnnitina D0.

. o-Toluidine Yellow. m-Toluidine D0. p-Toluidinn I Do.

2, l-dichloroaniline Do. 2, Miohlnmanilinn Orange-yellow. o-Nltro-pchloroaniline; Do. 4-nitro-2-methoxyanilinc a D0- p-Aminnnmtnphanrma Yellow. 2-methyl-4-nitmanlline Orange-yellow. 3.111tMm-ninntnhmnn D0, l-amlno-3-nltro-4-methyl benzene D0- 0-Aniidinn DO.

/ ni-Anisidinn D0.

- p-Anisidine D0- o-Chloroaniline D0. m-Chlomanflha D0. p-Chloroanlline D0. o-Bromoanllinc.- D m-Bromoaniline-- Do. p-Bromoanlline Do. o-Tnlnidina DO. m-Tnlniriinn DO. p-Toluidlne Do.

2, 4-dichloroanilinc. Yellow. 2, 5-dichloroanilinc.-. o-Nitro-p-chloraniline. D 4-nitro-2-mcthoxyanil1ne p.Aminm-nn .hannna 2-methyl-4-nitroanlline Do. 3-nitro-4-aminotoluene l-amino-il-nitro-l methyl benzene D @Anisidinn D p-Anisidlnc Do. O-Chlnmani'linn D0, m-ChlOrnanllinn 7 D0. p-Chloroanillnc.-. DO- 0-H. 'llnn D0. m-Bromoanilinc D p-Bromoanilino Do- Do o-T uidinc.. Do. Do m-Toluldinc--..- Do.

asv

Coupling component Amine g gg gfl lg l l loso d-iminobarbituric B015 p-Tnlnidina Yellow. 2, 4-dichlnrmmilinn D 2, fi-dichloroaniline o-nitro-p-ch1oroaniline 4-nitro-2-methoxyanilin p-Aminoacetpphenone.

Do. Orange-yellow.

Yellow:

2-methyl-4-n1troamlme. Orange-yellow. 3-nitro-4-aminotoluene Do. l-ammo 3-nitro-4-metl1yl benzene Do. o-Anisidine. Yellow. m-Anisidine. Do. p-Anisidine Do. o-Ohloroaniline.- D0. m-Chloroaniline Do. p-Chlornaniline D0. o-Bromoaniline Do. m-Bromoaniline Do. Brnmnm'iilins D0. o-Tcluidine Yellow. m-Toluidine. Do. p-Tnlniriine D0, 2, 4-dichioro aniline Do. 2, 5-dichloroani1ine. Do. o-Nitro-p-chioroanilme. Do. 4-nitro-2-methoxy :aniline.. Do. p-Aminoacetophenone D o. Orange-yellow.

Do. Do.

Compounds represented by Formula IV Coupling component Amine gg gg g hg z-lminobarbiturie mid o Anisirlina Greenish-yellow.

Do p-Anisid 0. Do p-Nitroan Golden-yellow. Do ONltl'OBllilillG. Yellow. Do m Nitroaniline- Do. Do Goldenyellow.

Greenish-yellow Red Green ish-yellow Golden-yellow.

I In employing the aromatic azo derivatives of our invention as dyes, they will ordinarily be applied to the material in the form of an aqueous suspension which can be prepared by grinding the dye to a paste in the presence of a sulfonated oil, soap, or other suitable dispersing agent and dispersing the resulting paste in water. Dyeing operations can, with advantage, be conducted at a temperature of 80-85 0., but any suitable temperature may be used. In accordance with the usual dyeing practice, the material to be dyed will ordinarily be added to the aqueous dye bath at a temperature lower than that at which the main portion of the dyeing is to be effected, a temperature approximating 4555 C., for exdye bath will be raised to that selected for carrying out the dyeing operation. The temperature at which the dyeing is conducted will vary somewhat, depending, for example, on the particular material or materials undergoing coloration;

The amount of dispersing agent employed may be varied over Wide limits. Amounts approximating to 200% by weight on the dye may be employed, for example. These amounts are not to be taken as limits as greater or lesser amounts can be used. To illustrate, if the dye is'ground to a sufiiciently fine powder dyeing can be satisfactorily carried out without the aid of a dispersing agent. Generally speaking, however, the use of a. dispersing agent is desirable.

Advantageously, dyeing is carried out in a substantially neutral dyebath. Perhaps, more accurately, it should be stated that dyeing should ins.

It will be understood that the azo compounds of our invention may be applied to the material to be colored in any suitable manner. Coloration may be efiected, for example, by dyeing, printor stenciling. Dispersing or solubilizing agents that can be employed for preparing suspensions of the dye include soap, sulphoricinoleic acid, salts of sulphoricinoleic acid, a water soluble salt of cellulose phthalate, cellulose succinate or cellulose mono-acetate diphthalate, for example, the sodium,. potassium or ammonium salts, and sulfonated oleic, stearic or palmitic acid, or salts thereof, such, for example, as the sodium or ammonium salts.

While it is preferred to effect coloration by applying the dye compound from an aqueous dye bath directly to the material to be colored, the azo compounds of our invention may be applied employing the methods applicable to the so-called ice colors. Briefly, in accordance with this method of dyeing, the amine is absorbed and diazotized on ,the fiber, after which the dye is formed in situ by developing with a coupling component such as barbituric acid, thiobarbiturlc acid, 2-imino-3-cyanobarbiturlc acid, B-iminobarbituric acid, 2-iminobarblturic acid .or 2- -alkyl-iminobarbituric acid, for example.. Cona,14o,sss I of cellulose acetate silk, m the form of tafieta or verselythe material undergoing dyeing or coloration may first be treated to absorb one of said parts by weight.

x, Example A 25 pounds of cellulose acetate in the form of taffeta are dyed on the jig, using 0.2 pound of o-methoxybenzeneazobarbituric acid dispersed in 70 gallons of water as the dye solution. The cloth is entered and passed twice through the solution at 100 F., and then the temperature is gradually raised to 200 F. and dyeing continued for one hour. The cloth is colored a greenish-yellow shade of excellent fastness to light. Para methoxybenzeneazobarbituric acid, for example. may be substituted for, o-methoxvbenzeneazobarbituric acid. This compound similarly yields-a greenish-yellow shade of very good iastness to light.

' Example B 0.2 pound of p-ethoxybenzeneazothiobarbituiic acid are finely ground with 2 pounds of a dis persing agent such as soap or oleyl glyceryl suliate and the resulting paste is dissolved in 100 gallons of water. Cloth consisting of a mixture of cellulose acetate and viscose yarns containing 15 poundsoi cellulose acetate yarn and pounds of viscose yarn are entered in the dyebath and subjected to the same dyeing conditions disclosed in Example 1. The acetate yarn is dyed orange yellow. The viscose yarn is not stained.

If it is desired to dye the visccse yarn, suitable dyes such as Amidazo Yellow 2GL, Chloramine Red 33, or Direct Blue 23 may be added to the dyebath. These dyes color the viscose yarn yellow, red, or blue and do not stain the acetate yarn. Cross-dye effects are thus readily obtained using dyes of the azo barbituric acid class on the cellulose acetate.

Example C 2.5 parts of the compound formed by coupling 2-imino-3-cyanobarbituricacid with o-anisidine are finely ground with soap and dispersed in 1000 parts of water. The dispersion'thus pre- Example D 2.5 parts of the dye compound formed by coupling diazotized o-anisidine with B-iminobarbituric acid in an alkaline medium are finely ground with soap. and dispensed in 1000 parts of water.

The dispersion thus prepared is heated to a temperature approximating 45-55 C. and 100 parts yellow shade.

threads, for example, are added to th dye bath, after which the temperature is gradua to 80-85 C. and the silk worked for several hours at this latter temperature. Upon completion of the dyeing operation, the cellulose acetate silk is removed, washed with soap, rinsed and dried. The cellulose acetate silk is dyed a greenish- Example E 2.5 parts of the compound'iormed by coupling 2-imino-barbituric acid with o-phenetidine in an alkaline medium are finely ground with soap and dispersed in 1000 parts or water. The dispersion thus prepared is heated to a temperature approximating 45-55" C. and 100'parts of cellulose acetate silk, in the form of taffeta or threads, for

example, are added to the dyebath, after which the temperature is gradually raised to 80-85 C. and the silk worked for several hours at this latter temperature. Upon completion of the dyeing operation, the cellulose acetate silk is removed, washed with soap, rinsed and dried. The cellulose acetate silk is dyed a greenish-yellow shade.

While our invention has been illustrated in connection with the dyeing of cellulose acetate silk it will be understood that dyeing operations can be-carried out in amannersimilar to that described above by the substitution of another organic derivative of cellulose material for cellulose acetate silk or by employing dye compounds other than those employed in the examples, or by substitution of both the material being dyed and the dye compounds of the examples.

We claim:

-l. The process of coloring organic derivativ of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated aromatic azo derivatives of barbituric acid and substituted barbituric acids.

2.- The process of coloring organic derivatives of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-suiionated aryl azo derivatives of barbituric acid and substituted barbituric acids.

3. The process of coloring organic derivatives of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulionated aryl-azo derivatives of barbitm'ic acid.

4. The process of coloring organic derivatives of cellulose which comprises app y thereto a nuclear non-sulfonated dye having the general formula:

AN =NB wherein A represents an aryl nucleus oi the benzene series and B represents a nucleus selected from the class consisting of barbituric acid and substituted barbituric acids.

5. The process of coloring organic derivatives of cellulose which comprises applying thereto a dye having the general formula:

wherein A represents a' nuclear non-sulfonated aryl nucleus of the benzene series.

11y raised.

6. The process of coloring organic derivatives of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated aryl azo derivatives of mmbarbituric acid. 7

7. The process of coloring organic derivatives of cellulose which comprises applying thereto a dye having the general formula:

wherein A represents a nuclear non-sulf onated aryl nucleus of the benzene series.

I 8. The process of coloring an organic acid ester of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated aryl azo derivatives of barbituric acid and substituted barbituric acids.

9. The process of coloring an organic acid ester of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated aryl azo derivatives of barbituric acid.

10. The process of coloring an organic acid ester of cellulose which comprises applying thereto a nuclear non-sulfonated dye having the general formula: AN=N-B wherein A represents an aryl nucleus of the benzene series and B represents a nucleus selected from the class consisting of barbituric acid and substituted barbituric acids.

11. The process of coloring an organic acid ester of cellulose which comprises applying thereto a dye having the general formula:

wherein A represents a nuclear non-sulfonated aryl nucleus of the benzene series.

12-. The process of coloring an organic acid.

ester of cellulose which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated'aryl azo derivatives of thiobarbituric acid.

13. The process of coloring an organic acid ester of cellulose which comprises applying thereto a; dye having the general formula:

0=c- N-H AN=N H (':=s

O=C'I IH wherein A represents a nuclear non-sulfonated,

aryl nucleus of the benzene series.

14. The process of coloring a cellulose acetate which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated aryl azo derivatives of barbituric acid and substituted barbituric acids.

15. The process of coloring a. cellulose acetate which comprises applying thereto a dye selected from the class consisting of the nuclear non-sulfonated aryl azo derivatives of barbituric acid.

16.- The process of coloring a cellulose acetate which comprises applying thereto a nuclear nonsulfonated dye having the general formula:

wherein A represents an aryl nucleus of the benzene series and B represents a nucleus selected from the class consisting of barbituric acid and substituted barbituric acids.

17. The process of coloring a cellulose acetate which comprises applying thereto a dye having the general formula:

. O=CNH AN=N H (':=s 0'=(IJI!IH wherein A represents a nuclear non-sulfonated aryl nucleus of the benzene series.

JALdES G. MCNALLY. JOSEPH B. DICEY. 

